High-Contrast Color-Stripe Pattern for Rapid Structured-Light Range Imaging

Abstract

For structured-light range imaging, color stripes can be used for increasing the number of distinguishable light patterns compared to binary BW stripes. Therefore, an appropriate use of color patterns can reduce the number of light projections and range imaging is achievable in single video frame or in "one shot". On the other hand, the reliability and range resolution attainable from color stripes is generally lower than those from multiply projected binary BW patterns since color contrast is affected by object color reflectance and ambient light. This paper presents new methods for selecting stripe colors and designing multiple-stripe patterns for "one-shot" and "two-shot" imaging. We show that maximizing color contrast between the stripes in one-shot imaging reduces the ambiguities resulting from colored object surfaces and limitations in sensor/projector resolution. Two-shot imaging adds an extra video frame and maximizes the color contrast between the first and second video frames to diminish the ambiguities even further. Experimental results demonstrate the effectiveness of the presented one-shot and two-shot color-stripe imaging schemes.

Dense 3D reconstruction method using a single pattern for fast moving object

“…Since they still require several patterns for identification, they are not suited for extremely fast objects. Techniques using only spatial encoding of a pattern are suitable for fast-moving objects, since they use only a single-frame image [9,16]. On the other hand, the problems are that they typically need complex patterns or colors to encode positional information.…”

“…Next, we decode the color code based on the de Bruijn sequence [9,15,19]. A q-ary de Bruijn sequence of order n is a sequence of length q n consisting of an alphabet of size q in which every possible subsequence of length n is present exactly once.…”

“…This reduces the matching candidates (by about 1/8 in the case of the implementation of this paper) and the stability of search of the solution is much stabilized. Note that, since the IDs are just used for additional information for 1D optimization, error of identification is not serious compared to previous color coding methods [9,15,19].…”

Active Stereo Vision for 3D Profile Measurement

“…The most commonly used primitives are color and geometry. Some of the color-based patterns are colored slit pattern, colored stripe pattern, colored grid pattern, colored spot pattern, etc (Tehrani et al, 2008;Pages et al, 2004;Je et al, 2004;Salvi, 1998;Payeur, 2009). The codeword of the each primitive is usually formulated under the constraint of De Bruijn sequence (Pages et al, 2004), pseudorandom sequence (Payeur, 2009) or M-arrays (Salvi, 1998).…”

Structured Light Methods for Underwater Imaging: Light Stripe Scanning and Photometric Stereo

“…However, very few techniques explicitly analyze the influence of scattering on the appearances of scenes under active illumination 1 . Structured lighting is also widely used in computer vision, for 3D reconstruction of scenes [25], [14], [4], [11], [27], [19], [20]. However, an implicit assumption made in most methods is that light is neither scattered nor absorbed by the medium in which the scene and sources are immersed (as in pure air).…”